MAIN DESIGN
This is my CAP 6 entry, whose design is inspired from the Frigate Bird.

SUPPORTING MATERIAL​

Relation to the CAP 6 Concept: "Show Me Your Moves!"
Going with the community's concept approach of making Belly Drum usable, I researched for an inspiration that is preferably organic because it MUST have a real belly, and could possibly be a striking characteristic. The Frigate Bird fit my criteria perfectly. Frigate Birds are known for their inflatable gular pouches tinted in vivid red, which makes a perfect catalyst for Belly Drum.

Design Justification

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Steel/Flying is a typing that also fit the bill for the Frigate Bird design. Because my inspiration is a frigate bird, I took its other meaning (navy ship) and applied it into the design. Using navy elements to justify its steel typing, I opted for the anchor beak as a central design feature, supported by the steel-plated admiral's coat.

This design is too Honchkrow!

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With which I quote myself:

It has been pointed out to me since the start that it does resemble Honchkrow. However, this does not automatically mean that it affects the integrity and/or originality of my design. If anything, I'm actually glad it resembles a pokemon since we're technically creating a pokemon here. But then again, I believe that my frigate bird has plenty of elements to differentiate itself from Honchkrow. Also if you're curious, there's a reason why I chose the black-and-red color scheme, which is based upon the natural colors of a frigate bird.

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I also want to add that this design has been done with the real-life frigate birds' physique in mind. In comparison, a little food for thought: why is Honchkrow fat when crows generally aren't?

But it kinda looks like Water/Flying because of the navy elements!

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I opted for the design approach being aware of this kind of feedback. It may have a vibe of Water/Flying, but I believe that it represents Steel/Flying better. And just a heads up: All Water-type birds have webbed feet. (See Golduck, Swanna, Empoleon) My Frigate Bird design, as well as its IRL inspiration, does not have webbed feet and thus are unable to swim.

Relation to Stats and Abilities

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This list shows that the Frigate Bird is one of the faster birds in terms of flight speed, reaching speeds of over 150 km/h. That speed, coupled by the sturdy-looking physique that my design exudes, goes well with the 130 DEF and 118 SPE stats. The 92 ATK means it's not a slouch on the offensive side either (see arms), while 50 HP just balances with the fact that pokemon birds in general have low hp stats. (See Swellow, Dodrio, Pelipper, and Farfetch'd among others)

Because of the Navy theme approach I did on the design, it ties in with the Intimidate ability very well. The inflatable red belly helps increase its mass too which can be used as intimidation. Volt Absorb is made possible through the “golden buttons” located on its frontal steel plating and the back near its vertebrae. These buttons conduct electricity and channel it around the body, which is converted into energy as well as preventing electricity to flow through the entirety of its body.

Pokemon Description
This Pokemon usually inflates its front to scare off other Pokemon that gets in its way. It then pounds its belly while letting out a shrill noise if the opponent doesn't back down, which Pokemon researchers observed as a last warning before it attacks the foe mercilessly.

There have been sightings of groups of this migratory Pokemon flying steadily through storms, unwavered by the intense lightning and powerful winds. Using its mass and its dangerously sharp steel beak, it swoops down in frightening speeds to pierce and capture prey that swims near the surface of the sea. It was believed that the anchors used by ships and vessels are inspired from the shape of this Pokemon's beak.

Overall I really had fun in creating, developing and finalizing this design as my second art entry to the CAP Project. I think Frigate Bird got quite its own fair share of good and bad points, all of which I appreciate wholeheartedly. I'm grateful for the support, critiques and suggestions given by everyone in this thread and in #cap IRC. Thanks everyone!

I greatly appreciate your organic design, Magistrum. All the metallic robot-like designs are off-putting personally. Even if this Pokemon is a Steel-type, I want it based on a lifeform rather than some inanimate metallic form shaped like a bird / rocket / motorbike... Your supporting material showcases the the fluidity of your CAP design to accommodate many aspects of this Pokemon's qualities.

Even with the organic feel, you were able to create a design that tactfully reinforces the CAP's Steel-typing, Intimidate ability, stat distribution, and particularly access to Belly Drum. I dig it :D

This design is based on a sea slug called Glaucusatlanticus (The article and pictures are really interesting I swear). I picked a sea creature because why not? The metallic, glittery color and 'wings' suit the Steel/Flying type pretty well I think.
Of course I had to adapt the features for an aerial creature with the given capabilities. I felt like I shouldn't change too much, as like I've said a few times, that thing is practically a Pokemon already.
I did an "Armaldo" on it, giving it a more reptilian body shape, which matches the slug's "sea lizard" moniker. Having large 'hands' and a prominent belly indicate its use of Belly Drum, while a plain-colored back (shown in the supplements) with a striking front, along with red eyes and a toothy smile makes for an intimidating appearance. I wasn't really prepared for Volt Absorb to be honest, but the patterns it has can also invoke electricity somewhat. Some abilities are more internal than external anyway.

I should probably explain the Pokemon I envisioned with this design.
These mons soar unimpeded (and upside-down like its inspiration) at very high altitudes, their reversed countershading and reflective skin effectively camouflaging them. Unlike other flying creatures, these Pokemon do not shy away from flying through thunderstorms, as their anatomy can redirect lightning strikes; excess electricity passing harmlessly through, and the rest getting absorbed as usable energy. They can feed on metal, absorbing and incorporating it into lattices in their tissues. They use the red organs on their wings to 'smell' the purity and type of metals, preferring to munch on lighter ones like titanium. In nature, they find it from ores from crags or mines, occasionally poaching rarer and purer metals from other Steel-types, making aggressive dive bombs and biting off small pieces of their prey's metallic hide. Some individuals have even acquired a taste for man-made structures, their telltale bite-marks having been found on hundreds of air- and watercraft, buildings, statues, and at least one submarine.

Final Submission
Paintseagull kindly made me aware of some artistic discrepancies that would make my design illegible for the poll, so here's the new and improved version of Steelberry.
Again, it flies by using its strawberry stem as a rotor. Its many screws, both around its body and to form its eyes, represent how tough it is with its physical defense; contrary to a strawberry's supposed mushy nature, this steelberry can take any beating an opponent can dish out.
The steel spikes on its feet were added as a nod to this strawberry's harsher aspects; this is one strawberry you wouldn't want to digest.
This thing is certainly terrifying enough to justify Intimidate, and I feel Volt Absorb could work either via the metal stem-rotor or the foot-spikes. This design is also... wait for it.... shockingly good, so that's good flavor with Volt Absorb.
Finally, this thing can use Belly Drum in two ways; first, its flexible legs could bash its lower torso. Second, and more intriguingly, steelberry could slightly unscrew its own "seeds" so they're hanging out, then pull them back in very quickly. This would create a sharp banging sound similar to a drum.
I have supreme confidence in my steelberry's ability to triumph in the poll, in our hearts and (hopefully) our votes.
To steel-victor-berry, and excellent CAP submissions all around,
StrawberryLover69

This is a colored version of Pigasus, and my final submission. I've made the basic color a brownish-red to emphazize its aggressive, boar-like nature. The chestplate is a muted gray rather than a shining silver, so as to blend in more naturally with the body and add some variety to the color scheme. Pigasus's gold mask adds some great highlight to the design, and along with its hair gives it a very Spartan warrior feel. Boars and flying pigs were often monsters in Greek mythology, so that gives it tons of flavor options for naming and Pokedex entries.
Pigasus's wings are spiked with the same deep metal as the chestplate. This adds to the intimidating nature of the design (which already certainly is scary enough to justify the ability) but more importantly it adds the option of Volt Absorb. I can totally imagine a Pikachu's Thunderbolt heading towards Pigasus, then veering off to a wing spike, which absorbs it to supercharge Pigasus's health. Pigasus's gold tusks could also work in this way.
Good look to all!

So to reiterate, this is a jetplaneified Sharovipteryx, Ancient gliding reptile of mysterious provenance. Thought having legs as wings would free it up for Bullet Punch and such nonsense. Anyway, Here's some other doodles, and good luck to you all!

This design takes Steel elements from the metallic parts of its umbrella, its umbrella-handle-like arms and its hollow round steel body. Its Flying elements come from its ability to be carried by the wind by its large umbrella hood. It can control its movement in the air by increasing or decreasing the amount the umbrella is stretched out, or even by flipping the umbrella inside out! It also uses its ribbons for steering.

The design invokes Volt Absorb by being thematically linked to rain storms and lightning. Its has a tall metal pole that can act as a conductor, and can absorb energy into its hollow body.

It invokes Intimidate by presenting a large, false face that confuses and scares other pokemon that might not otherwise be afraid of it.

The umbrella-handle-like arms can bend and can be used to drum on the hollow body so that it can use Belly Drum.

Super Moderator

Sorry, but I had way too much fun with this design. Kiwis are my favorite bird, and this idea just had to be done. I wanted to go in a chivalrous route, so I went for a bit of a knight-ly theme, complete with helmet and sword beak. Its claws and beak provide a serious physical onslaught, while its helmet and wing covers provide it with some notable defenses. The coloration of this bird is bright, which is an indication not to be trifled with. It can smack its colorful belly with the flat end of its sword (but even that is sharp enough to do a bit of damage).

Supporting Material
Hey guys! As some of you might have noticed, I haven't spent any time at all on the smogon forums lately. I'm so busy with projects (at school/work) that I just didn't have time to finalize/adjust my previous design.
So here is my (old) submission! Please don't shoot me;);)

Concept
The concept is a blind bird of prey disguised as a parrot. It plays on its xylophone belly to scan its surroundings. Once the xylomon has found an enemy it will charge forward with its claws.

Stats and ability justification

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Stats:
HP: Like magistrum mention already: bird pokemon tend to have low HP. Also, behind its sturdy belly and protecting cloak, there's a frail squishy bird to be found;)
Attack: The bird's big beak, claws and wings can be used for powerful physical hits
Defense: The steel belly provides it with high natural defense
Sp. Attack: --
Sp. Defense: Although its cloak can give some resistance to special attacks, it won't defend it against powerful special hits
Speed: The mon is partly based on eagles, which are naturally fast. I see it like it might not be that fast on land, but once it charges down from the sky it can reach extremely high speeds.

Abilities:
Intimidate: The spooky empty eye pattern on it's cloak is used to scare away foes.
Volt absorb: The red thread that goes from it's head all the way through it's body down to its tail "feathers" can be used to channel electricity to provide the xylomon with extra energy.

The pokemon world is a bit lacking in instrument-based pokemon, so this design is based on a metallic, percussive drum. The cymbal-esque shape above its drum-face is actually a series of helicopter-like propellers spinning at high speed. Its signature move? Yes, Belly Drum.

It's ready to play some air drums/perform drum solos on its opponents' faces. (Maybe it even has a gear to grind.)

I haven't had much time lately, but I joined Team Rocket and incorporated several drastic changes in my design to fit the stats and abilities. The horn is there to fit both abilities and in case it wanted to Drill Peck things. Hope it can be more clear than the previous design.